The present invention relates to reaction of carbon monoxide with formaldehyde, preferably in the presence of water, to obtain hydroxyacetic acid.
Hydroxyacetic acid has various known uses and can be used to make ethylene glycol. In the reaction steps important to the current commercial production of hydroxyacetic acid, formaldehyde is reacted with carbon monoxide and water in the presence of an acidic catalyst such as sulfuric acid at a high pressure, above 4500 psi, and at a temperature usually between about 150.degree. and 225.degree. C.
U.S. Pat. Nos. 2,152,852; 2,153,064; and 2,265,945 disclose hydroxyacetic acid production from formaldehyde, carbon monoxide and water using acid catalysts. According to all three of these patents, the acid catalysts disclosed are hydrochloric, sulfuric, phosphoric and inorganic acid salts such as potassium acid sulfate, sodium acid phosphate and boron fluoride. Temperatures disclosed for use in the processes of the patents are 50.degree. to 350.degree. C and more preferably 140.degree. to 225.degree. C. Pressures disclosed are 5 to 1500 atmospheres (75 to 23,000 psi) and higher. In the examples of all three of the patents, the only inorganic acid catalysts used are phosphoric acid, sulfuric acid and hydrochloric acid. The temperatures used in the examples of the patents usually are between 160.degree. and 200.degree. C; and the pressures usually about 900 (13,500 psi) atmospheres and essentially always above 300 atmospheres (4500 psi). The severe reaction conditions indicated for the carbonylation of formaldehyde such as the high reaction temperature in the presence of corrosive acids and very high CO pressure require expensive equipment made from corrosive-resistant materials. According to the disclosure in the patents, the reaction can be effected in a continuous manner by passing the formaldehyde or its equivalent, water or its equivalent, and acid catalyst through a reaction zone either cocurrently or counter-currently to the flow of carbon monoxide.